Cognitive Impairment and Peripheral Neuropathy by Mixed Organic Solvents in Spray Painters Working in a Shipbuilding Industry

BACKGROUND: Exposure to organic solvents becomes a common problem to workers of heavy industries in Korea. A number of volatile organic solvents which are frequently used in painting can cause various derangements of the nervous system, especially cognitive impairments and peripheral neuropathy. METHODS: This study was carried out on 190 workers as a control group who had never been exposed to organic solvents and on 674 spray painters with long-term exposure to organic solvent mixtures. The major components of organic solvent mixtures were determined. All subjects underwent neurological examination as well as routine physical check-up after completing questionnaires on general, musculoskeletal, neuropsychiatric and neurological systems. Subjects with abnormal findings on neurological examination related with the exposure of organic solvent mixtures took further neuropsychological and neurophysiological tests. RESULTS: The prevalence rates of cognitive impairments and of peripheral neuropathy in the exposed group were significantly higher than the control group (9.5% vs 2.1% and 2.1% vs 0%, respectively). High exposure group (more than 2.64 of cumulative exposure index, CEI) showed also higher prevalence of cognitive impairments and of peripheral neuropathy than low exposure group (cognitive impairments; 12.3% vs 6.4%, peripheral neuropathy; 2.3% vs 1.8%). Most common cognitive impairments were attentional deficit, and abnormal sense on the extremities or face was most common symptom of the peripheral nervous system. CONCLUSION: This study is the first large-scale, case-control study extensively evaluating cognitive impairments and peripheral neuropathy related with volatile organic solvent mixtures in spray painters working in a shipbuilding industry in Korea. The results show that the prevalence rates of cognitive impairments and of peripheral neuropathy are relatively low, but clearly related with the exposure extent of organic solvents.

Changes of Memory in Adult by Aging

Though congitive functions of a man decline in normal aging and memory decline is the most common complaint of an elderly, the status of quantitive and qualitative estimates of these are rare in Korea. To assess the qualitative and quantitive aspect of changes of memory in aging, neuropsychological tests about memory functions were performed and the results were.analyzed in healthy adult volunteers of 20 to 9 year-old, having no evidence-of organic brain dysfunction. The scores of each tests.are lower than that of English-speaking countries, but memory functions declined significantly in normal aging and the qualitative aspect of these are characteristics. Contrary to the western reports. The visuospatial memory declined significantly before the age of 50 and the verbal memory after 50 in aging. So we should take care in screening and diagnosis of dementia and amnesia using these neuropsychological test in Korea.

Relative Bioavailability of Controlled Release Carbamazepine and Pharmacokinetic Properites: Steady-State Study

The relative bioavailability amd palsma level fluctuation of controlled release carbamazepine (carbamazepine CR, CBZ CR, Tegretol CR) to the regular product (Carbamazepine RR, CBZ RR, Tegletol RR) were studied in 12 patients who were taking stable dose of carbamazepine for more than six weeks. Fixed dosage regimen (400 mg every 12 hours) of both products was administered in a random cross over manner at least for four days. After reaching steady-state, serial blood samples were drawn after last dose administration. Plasma carbamazepine levels were analysed by fluorescence polarizing immunoassay. The controlled lelease products showed lower area under the concentration time curve (AUC; 89.7)20.0 ug/ml/hr) than that (107.1)13.2 ug/ml/hr) of the regular products (p<0.01), and also showed low peak plasma level (CR;848)l.93ug/ml, RR;10.57+1.55 ug/ml). However. Fluctuation of plasma drug level during dose interval was slightly less in controlled release products compared with carbamazepine regular products in the respect of various indices such as percent fluctuation, fluctuation index and area deviation from mean level. However those parameters did not show no statistical singificance between two products except area diviation (p<0.01). Though the controlled relase product showed slightly less fluctuation during dose interval, this seemed to be the expense of incomplete bioavailability. As a conclusion, the dose correction should be made according to the relative bioavailability of controlled release formulation if switching of the formulation from regular to controlled release form would be needed. However it could not be proved that controlled release fromulation had less fluctiuation during dose interval in this study. More detailed studies should be pursued to show the evidence of significant superiority of currently marketing controlled release formulation to the regular one.